Answer:
4
Step-by-step explanation:
You call the number x. Then you do (x-7) * 3=-9.
3x-21=-9
3x=12
x=4
Answer:
6.46
Step-by-step explanation:
h(t) = (1/2)
+ v0t + h0
Origin is at surface of water (h = 0), up is positive.
a = -g = -9.8 m/
v0 = 25 m/s
h0 = 50 m
h(t) = -4.9t2 + 25t + 50
Find t when
7 =
+ 25t + 50
- 25t - 43 = 0
t = [1/(2*4.9)] [25 ±√(
+ 4*4.9*43)]
t = (0.102)(25 ± 38.312)
t > 0 ⇒ use only the positive square root
t = (0.102)(25 + 38.312) ≅ 6.46 s
It is 7m above the water at about 6.46 s